Lithium secondary batteries are widely used and can be found in laptop computers, cameras, camcorders, PDAs, cell phones, iPods and other portable electronic devices. These batteries are also growing in popularity for defense, automotive and aerospace applications because of their high energy density.
Lithium phosphate-based cathode materials for secondary battery have long been known in the battery industry. People have used metal intercalation compound to improve the electrical property of lithium phosphate. One popular intercalation compound is lithium iron phosphate (LiFePO4). Because of its non-toxicity, thermal stability, safety characteristics and good electrochemical performance, there is a growing demand for rechargeable lithium secondary batteries with LiFePO4 as the cathode material.
The present invention teaches a better method of making lithium iron phosphate and other metal intercalation compound for cathode materials of secondary batteries. The prior art methods often result in incomplete reduction of trivalent iron (Fe3+). This incomplete reduction causes poor electrical performance of the battery, especially when high electrical discharge is required such as for batteries used in electrical vehicles.
As such, there is a need for a better manufacturing process for lithium iron phosphate cathode material.